Rockwell Automation 1761 MicroLogix 1000 Programmable Controllers - Manual (Page 100)

Preface MicroLogix 1000 Programmable Controllers User Manual
6–2
Timer/Counter Instructions
Instruction
Purpose Page
Mnemonic Name
Purpose Page
TON Timer On-Delay Counts timebase intervals when the instruction is
true. 6–11
TOF Timer Off-Delay Counts timebase intervals when the instruction is
false. 6–12
RTO Retentive Timer Counts timebase intervals when the instruction is
true and retains the accumulated value when the
instruction goes false or when power cycle occurs. 6–14
CTU Count Up Increments the accumulated value at each false-to-
true transition and retains the accumulated value
when the instruction goes false or when power cycle
occurs. 6–18
CTD Count Down Decrements the accumulate value at each false-to-
true transition and retains the accumulated value
when the instruction goes false or when power cycle
occurs. 6–19
RES Reset Resets the accumulated value and status bits of a
timer or counter. Do not use with TOF timers. 6–20
About the Basic Instructions
These instructions, when used in ladder programs represent hardwired logic circuits
used for the control of a machine or equipment.
The basic instructions are separated into three groups: bit, timer, and counter.
Before you learn about the instructions in each of these groups, we suggest that you
read the overview that precedes the group:
•
Bit Instructions Overview
•
Timer Instructions Overview
•
Counter Instructions Overview